Tdap Vaccine Is Not Associated with Premature Delivery

by Marygrace Taylor on November 17, 2014

Marygrace Taylor

About the Author

Marygrace Taylor is a Connecticut-based health writer who has worked for KIWI magazine, New Parent magazine and Prevention.com. Visit her at <a href="http://marygracetaylor.com/" target="_new">marygracetaylor.com</a>.

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WhatToExpect.com supports Word of Mom as a place to share stories and highlight the many perspectives and experiences of pregnancy and parenting. However, the opinions expressed in this section are those of individual writers and do not reflect the views of Heidi Murkoff of the What to Expect brand.

Summary: New findings confirm that the Tdap vaccine doesn't increase the risk for preterm birth — and all moms-to-be should get it, experts say.

Across the U.S., recent outbreaks of pertussis, or whooping cough, prompted the CDC to begin recommending last year that all women receive the Tdap vaccine between 27 through 36 weeks of pregnancy. And now, new research is confirming that this step helps to protect the health of moms-to-be and their babies. Getting the tetanus, diptheria, and pertussis (Tdap) vaccine during pregnancy is not associated with an increased risk for preterm birth, according to new findings published in the Journal of the American Medical Association.

Researchers analyzed health data for over 26,000 pregnant women who were given the vaccine, as well as more than 97,000 pregnant women who were not given the vaccine. Among all of the pregnancies, they found that:

Rates of preterm birth were nearly the same: 6.3 percent of women who received the vaccine gave birth at 36 weeks or earlier, compared to 7.8 percent of women who had not gotten the vaccine

Roughly 8 percent of women in both groups had small-for-gestational age births

Getting the Tdap vaccine did yield a slightly higher association with a chorioamnionitis diagnosis, a bacterial infection that causes inflammation of the amniotic fluid and the membranes that surround the fetus. Just over 6 percent of pregnant moms who received the immunization were diagnosed with chorioamnionitis, compared to 5.5 percent of moms who hadn't gotten the shot. But while this sounds a little scary, doctors say you shouldn't be concerned. Here's why: It's not uncommon for women to show symptoms of chorioamnionitis — like fever — without actually having the condition. And since a vaccine has the potential to temporarily cause inflammation and a low-grade fever, these symptoms may have lead doctors to diagnose the condition even when moms didn't have the infection.

"We can say that the vaccinated women had higher rates of being diagnosed with chorioamnionitis, but it may be an association that's explained by other things, not necessarily the vaccines. There's no way to think that a vaccine could give you a bacterial infection," says lead study author Elyse O. Kharbanda, M.D., M.P.H., of the HealthPartners Institute for Education and Research in Minneapolis.

Further clinical trials will help researchers learn more about the relationship between chorioamnionitis and the Tdap vaccine. In the meantime, Kharbanda emphasizes that the potential association should not stop moms-to-be from getting vaccinated. "The findings related to chorioamnionitis haven't been confirmed, and there are many other likely explanations," she says. "The study has been peer-reviewed, reviewed by immunization experts and went through CDC clearance. I would reaffirm that the benefits far outweigh the risks."

Indeed, another study earlier this year found that pregnant moms who received the Tdap vaccine in their third trimester were not at any increased risk of harmful side effects. What's more, the research showed that infants born to moms who had the vaccine during pregnancy were better protected against whooping cough at birth and at 2 months old. More research out of Australia this year also found that when moms and dads of newborns were adequately vaccinated with the Tdap booster, their babies were 50 percent less likely to catch the disease compared to babies whose parents weren't vaccinated — important since your infant is at risk of infection until he gets a few doses of the vaccine and builds up his immunity.

Bottom line: You, your partner and any of your baby's potential caregivers should get the Tdap vaccine while you're expecting. It's one of the best ways to protect your little one's health.

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